2. Gwyneth Paltrow in Stella McCartney, 2008

“Paltrow gives the illusion of giving something away, while still having a kind of ladylike reserve," says InStyle fashion director Hal Rubenstein. "This sexy mini, by pal Stella McCartney, plays up her best assets and shows off her killer body.”

Pascal Le Segretain/Getty Images

3. Gwyneth Paltrow in Donna Karan, 2009

WHY WE LOVE IT "This gown was custom-made for Gwyneth," says Donna Karan of her design. "It's so ethereal and perfect with her coloring."

Romaniello/Venturelli/Olycom/iPhoto

4. Gwyneth Paltrow in Lanvin, 2008

WHY WE LOVE IT Leave it to Mrs. Chris Martin to give Lanvin's goddess dress a rocker edge with Balmain gladiator heels.

Gilbert Flores/CelebrityPhoto

5. Gwyneth Paltrow in Stella McCartney, 2005

WHY WE LOVE IT This Stella McCartney seems fit for a 21st-century princess, worn with deco-inspired diamonds and a structured clutch.

Venturelli/WireImage

6. Gwyneth Paltrow in Marni, 2009

WHY WE LOVE IT In Marni at an event in Milan, she changes up her natural beauty routine with red lips, dark nails, and an angled bob.

Camilla Morandi/Rex USA

7. Gwyneth Paltrow in Valentino, 2002

WHY WE LOVE IT Sleek equals stunning: At the Venice Film Festival, the star wears this Valentino number with straight hair and a leather cuff.

Christopher Peterson/BuzzFoto/FilmMagic

8. Gwyneth Paltrow in Alice + Olivia, 2009

WHY WE LOVE IT Unafraid to try out new trends, Paltrow combines two cool ones in an Alice + Olivia metallic trench and Christian Louboutin cage heels.

Ke.Mazur/WireImage

9. Gwyneth Paltrow in Calvin Klein, 1996

WHY WE LOVE IT In this Calvin Klein gown at the Oscars, she shows a "love for sensual simplicity" that "makes this woman a classic," says Klein.

Richard Young/Rex USA

10. Gwyneth Paltrow in Balenciaga, 2005

WHY WE LOVE IT Her choice of Balenciaga's long military coat, ruffled top, and cropped pants is just the right mix of masculine and feminine.

Sipa

11. Gwyneth Paltrow in Elie Saab, 2010

WHY WE LOVE IT With minimal jewelry and her hair pulled back, the mom of two lets this crystal-embroidered Elie Saab take center stage.

BEImages

12. Julia Roberts in Valentino, 2001

“Instead of using a stylist to pick a gown for her Oscar-winning night, Roberts turned to her niece, Emma. This Valentino number gave a huge boost to vintage," says InStyle fashion director Hal Rubenstein.

Ron Cruz/Thomas Lau

13. Julia Roberts in Giorgio Armani, 2004

WHY WE LOVE IT The mom-to-be glowed at the Oscars in a simple yet stunning Giorgio Armani satin gown and Cathy Waterman earrings.

Villard/Sipa

14. Julia Roberts in Lanvin, 2009

WHY WE LOVE IT Cartier jewels gave a luxe touch to her Lanvin gown, but she kept it casually chic with her loose, wavy hairstyle.

Krista Kennell/Eyedea

15. Julia Roberts in Vivienne Tam, 1999

WHY WE LOVE IT At the London première of Notting Hill, the Georgia native set off a vibrant Vivienne Tam sheath with black accessories.

Paul Smith/Retna

16. Julia Roberts in Calvin Klein, 1999

WHY WE LOVE IT Roberts showed that understated doesn't have to mean boring in this sleek Calvin Klein dress. A pink shawl adds punch.

Steve Granitz Archive/WireImage

17. Julia Roberts in Isaac Mizrahi, 1998

WHY WE LOVE IT The actress wore Isaac Mizrahi to accept her sixth People's Choice Award, finishing the look with a ladylike updo.

Dimitrios Kambouris/WireImage

18. Julia Roberts in Georgio Armani Privé, 2008

WHY WE LOVE IT For the Costume Institute Gala, the co-host opted for full-on glamour in a Giorgio Armani Privé gown. Love the brooch!

Steve Finn/Globe Photos

19. Julia Roberts in Giorgio Armani, 2002

WHY WE LOVE IT Her black Giorgio Armani Oscar gown was anything but basic thanks to an up-to-there slit and two well-placed cutouts.

Venturelli/WireImage

20. Diane Kruger in Vivienne Westwood, 2012

WHY WE LOVE IT: Kruger was dripping in (rose) gold as she walked the red carpet at the Cannes premiere of Amour in a Vivienne Westwood draped gown, matching clutch and diamond drop earrings.

Globe Photos

21. Julia Roberts in Todd Oldham, 1998

WHY WE LOVE IT Though she once said "I'll never be a risk taker in fashion," Roberts sparkled in this look-at-me Todd Oldham creation.

Gilbert Flores/CelebrityPhoto

22. Julia Roberts in Yves Saint Laurent and Esther Chen, 2002

WHY WE LOVE IT The secret newlywed hid her ring at a film première with the help of a bell-sleeve YSL blouse and Esther Chen pants.

Erik C Pendzich/Rex USA

23. Kate Moss in Dior, 2005

“On the one hand this Dior couture dress is lingerie-inspired and sexy, yet the shape is quite simple. Finishing off the look with tousled bed-head proves that Moss’s instincts are always right," InStyle fashion director Hal Rubenstein says.

Bauer-Griffin

24. Kate Moss in Kate Moss for Topshop, 2007

WHY WE LOVE IT The budding designer works the crowd in a shift with glittering fringe from her Kate Moss Topshop Collection.

Sean Roberts/Everett Collection

25. Kate Moss, 1998

WHY WE LOVE IT Smitten by Julie Christie's dress in Shampoo, Moss dons a striking replica for the CFDA Awards in New York City.

Wenn

26. Kate Moss in Chanel, 2008

WHY WE LOVE IT "Never a fashion victim and the ultimate modern girl," says Karl Lagerfeld of the model, here in his Chanel Haute Couture gown.

Dimitrios Kambouris/WireImage

27. Kate Moss in Siwy and Alexander McQueen, 2008

WHY WE LOVE IT Siwy jeans and a feathered Alexander McQueen vest with a Renee Lewis pendant are casual cool personified.

ABACAUSA

28. Kate Moss in Fendi, 2009

WHY WE LOVE IT At the Fendi O' party for singer Beth Ditto, the trendsetter is a silver stroke of genius in a Fendi dress, fur and shoes.

Bauer-Griffin

29. Kate Moss in Chanel and Marc Jacobs, 2007

WHY WE LOVE IT In a Chanel blouse, Marc Jacobs trousers and her own Topshop belt, she embodies a key commandment: Thou shalt mix high and low.

Sipa

30. Kate Moss in Cerruti, 1997

WHY WE LOVE IT In stark contrast to the Cannes Film Festival's red-carpet glitz, Moss turns heads in a minimalist gray Cerruti sheath.

31. Kate Moss in Kate Moss for Topshop, 2009

32. Kate Moss in Burberry Prorsum, 2006

WHY WE LOVE IT "We wanted something understated but elegant," says Christopher Bailey of the Burberry Prorsum tux he created for the Costume Institute ball.

Frederick M. Brown/Getty Images

33. Jennifer Aniston in Burberry Prorsum, 2009

“I love the idea of androgyny," says InStyle fashion director Hal Rubenstein. "And if you’re going to do menswear, you have to sex it up. Aniston really played against type in this Burberry Prorsum pantsuit.”

Chris Delmas

34. Jennifer Aniston in Christian Dior, 2002

WHY WE LOVE IT After winning her Emmy in vintage Christian Dior, the actress donated her gown to a charity auction, fetching $50,000 for Unicef.

Janet Gough/CelebrityPhoto

35. Jennifer Aniston in Chanel, 2007

WHY WE LOVE IT The star accepted the Vanguard Award in this seductive Chanel Haute Couture mini at a GLAAD event.

44. Beyoncé in Balmain, 2009

45. Beyoncé in Armani Privé, 2008

WHY WE LOVE IT At the Met Costume Institute Gala, the star made a statement in an Armani Privé gown with a dramatic side ruffle.

Humberto Carreno/Startraks

46. Beyonce in Elie Saab, 2009

WHY WE LOVE IT For an appearance on The Late Show with David Letterman, Mrs. Jay-Z looked demure in a soft Elie Saab dress.

Jennifer Graylock/STR

47. Beyoncé in Oscar de la Renta, 2005

WHY WE LOVE IT The Houston native exuded casual charm in an Oscar de la Renta skirt at the designer's runway show.

Steve Granitz/WireImage

48. Beyoncé in Atelier Versace, 2005

WHY WE LOVE IT Before performing onstage at the Oscars, the artist made an entrance on the red carpet in vintage Atelier Versace.

Stewart Cook/Rex Features

49. Beyoncé in Roberto Cavalli, 2004

WHY WE LOVE IT "She knows what works for her and always looks put together," says Roberto Cavalli of Beyoncé in his charmeuse gown.

Amanda Schwab/Startraks

50. Beyoncé in House of Deréon, 2008

WHY WE LOVE IT A little black dress from her House of Deréon line has a sexy appeal with bold diamond drop earrings.

Eric Gaillard

51. Beyonce in Emporio Armani, 2004

WHY WE LOVE IT Beyoncé understands the power of a bright palette. Witness this turn in a cotton-candy-colored Emporio Armani mini.

Kristie Bull/Graylock.com

52. Beyoncé in Roberto Cavalli, 2009

WHY WE LOVE IT Even rainwear looks chic when she wears it—like this Jillian Lewis trench thrown over a dress by Roberto Cavalli.

Frazer Harrison/Getty Images

53. In Christian Dior, 2010

At the Golden Globe Awards, Marion stood out in a dark teal Christian Dior gown that featured a high front slit and lace details.

Patrick Rideaux/Rex USA

54. Marion Cotillard in Nina Ricci, 2008

WHY WE LOVE IT Her long diamond necklace by Chopard contrasts with the soft ruffles and asymmetrical hem of a Nina Ricci dress.

Peter Brooker/Rex USA

55. Marion Cotillard in Jean Paul Gaultier, 2008

WHY WE LOVE IT She mastered (musical) scales in La Vie en Rose and perfects them in Gaultier Paris's mermaid gown at the Oscars.

Marion Curtis/Startraks

56. Marion Cotillard in Chanel, 2007

WHY WE LOVE IT This Chanel Haute Couture number is captivating, but it's the Oscar winner's eyes, enhanced with smoky shadow, that truly draw us in.

Dimitrios Kambouris/FilmMagic

57. Marion Cotillard in Dior, 2010

WHY WE LOVE IT No jewelry required: The face of the Lady Dior line shines in a sequin-covered haute couture stunner with a built-in necklace.

Mikah/Globe Photos

58. Marion Cotillard in Elie Saab, 2008

WHY WE LOVE IT "She looks very retro in this print," says Elie Saab of Cotillard in his design. "But the belt gives it a modern feel."

Julien M. Hekimian/Getty Images

59. Marion Cotillard in Lanvin, 2009

WHY WE LOVE IT Mademoiselle Cotillard tweaks an elegant draped Lanvin dress with strappy sandals for a party in Paris.

Tony Barson/WireImage

60. Marion Cotillard in Lefranc Ferrant, 2010

WHY WE LOVE IT The actress is as daring with fashion as she is with her film roles: Witness this metallic Lefranc Ferrant jumpsuit and twisted do in Cannes.

61. Marion Cotillard in Dior, 2009

WHY WE LOVE IT She toes the line between ladylike and hip in a pink Dior shirtwaist dress with John Galliano velvet and crystal platforms.

Sipa

62. Marion Cotillard in Giorgio Armani Privé, 2007

WHY WE LOVE IT A diaphanous Giorgio Armani Privé gown and loose tendrils push the star into romantic territory at an event in Berlin.

Gilbert Flores/CelebrityPhoto.com

63. Penelope Cruz in Atelier Versace, 2007

“The beautiful pink color of this Atelier Versace gown perfectly accents Cruz’s skin, while the silhouette manages to be both sleek and romantic at the same time," says InStyle fashion director Hal Rubenstein.

Eric Ryan/Getty Images

64. Penelope Cruz in L'Wren Scott, 2008

WHY WE LOVE IT Proving a penchant for detail, Cruz matched the burgundy velvet heels perfectly with her L'Wren Scott dress.

Jen Lowery/Startraks

65. Penelope Cruz in Chanel, 2008

WHY WE LOVE IT A fan of Chanel Haute Couture, the best supporting actress winner chose the iconic label for a trip down the Oscar red carpet.

Axelle Woussen/Bauer-Griffin

66. Penelope Cruz in Dolce & Gabbana, 2009

WHY WE LOVE IT Dolce & Gabbana made this custom dress for a Cannes event. "It shows off her natural beauty," says Stefano Gabbana.

Tony Barson/WireImage

67. Penelope Cruz in Marchesa, 2009

WHY WE LOVE IT Cruz donned a Marchesa confection for the premiere of Broken Embraces, her fifth film with director Pedro Almodovar.

Lisa O'Connor/Zuma Press

68. Penelope Cruz in Yves Saint Laurent, 2009

WHY WE LOVE IT Only a renaissance woman who speaks four languages can make an Yves Saint Laurent menswear look feel as sexy as any dress.

Niviere/Villard/Sipa

69. Penelope Cruz in Dior, 2003

WHY WE LOVE IT Already a star in Spain, Cruz was on the verge of international acclaim. She presented herself to the world in Dior Haute Couture.

Dan Steinberg/FilmMagic

70. Penelope Cruz in Michael Kors, 2007

WHY WE LOVE IT In a sunny Michael Kors mini, the Madrid-born beauty reveals style choices that show as much range as her acting skills.

Daniel Deme/WENN

71. Penelope Cruz in Oscar de la Renta, 2007

WHY WE LOVE IT "Poised and confident," says Oscar de la Renta of Cruz in his creation. "You don't just see the dress, you see her."

Jeff Vespa/WireImage

72. Penelope Cruz in Giorgio Armani, 2007

WHY WE LOVE IT The Vicky Cristina Barcelona star was drawn to this fiery Armani number for the designer's fashion show in L.A.

Baverel-Garcia/Starface/Retna Ltd.

73. Natalie Portman in Givenchy

“Portman doesn’t look like most young stars," says InStyle fashion director Hal Rubenstein. "She likes to play with volume and proportion. Here, she takes a wild Haute Couture look by Riccardo Tisci for Givenchy and pairs it with perfectly polished hair and makeup.”

Karwai Tang/Landov

74. Natalie Portman in Lanvin, 2008

WHY WE LOVE IT In Lanvin, she hit the Cannes Film Festival and made it her runway-one we want to see her on again and again.

Nick Sadler/Startraks

75. Natalie Portman in Christian Lacroix, 2008

WHY WE LOVE IT "She looks like modern royalty," Christian Lacroix says of Portman, here in his design. "She's special and timeless."

Grayson Alexander

76. Natalie Portman in Prada, 2003

WHY WE LOVE IT Always the risk taker, the actress is as comfortable in a Prada flapper dress as she is in a T-shirt and jeans.

Adam Orchon/Elevation Photos

77. Natalie Portman in Rodarte, 2009

WHY WE LOVE IT Ben Stiller's Joaquin Phoenix Oscar send-up got the laughs, but all eyes were on his co-presenter's Rodarte stunner.

Hahn/Khayat/ABACAUSA.COM

78. Natalie Portman in Chanel, 2006

WHY WE LOVE IT Long locks, begone! Her short hair looked fresh with vintage Chanel Haute Couture at the Golden Globes.

Hahn/Khayat/ABACAUSA.COM

79. Natalie Portman in Lanvin, 2005

WHY WE LOVE IT Lanvin's pleated gown was part of a big moment for the then 23-year-old-her nod at the Oscars for Closer.

Anthony G. Moore/PR Photos

80. Natalie Portman in Elizabeth and James, 2007

WHY WE LOVE IT Proving she can have fun with her look, she was pretty and playful in an Elizabeth and James mini at a New York premiere.

Chris Daniels/Retna

81. Natalie Portman in Lanvin, 2006

WHY WE LOVE IT Portman is close with Alber Elbaz, often wearing his Lanvin creations to events, like this origami dress.

Sonia Moskowitz/Globe Photos

82. Natalie Portman in Yves Saint Laurent, 2007

WHY WE LOVE IT What else would the star wear to the premiere of her indie French film, Paris, je t'aime? Yves Saint Laurent, mais oui!

SGranitz/WireImage.com

83. Nicole Kidman in Yves Saint Laurent, 2003

“Kidman has a fearless approach to fashion. The lavender color of this YSL gown offsets her red hair, while the silhouette is a nice play on proportion," says InStyle fashion director Hal Rubenstein.

Hahn-Khayat/ABACA

84. Nicole Kidman in Gucci, 2005

WHY WE LOVE IT For the Golden Globes, the star personalized her teal Gucci gown by adding a peacock feather to the bodice.

92. Nicole Kidman in Dolce & Gabbana, 2002

93. Anne Hathaway in Giorgio Armani Privé, 2009

"This Armani Prive dress has huge wow factor, says InStyle fashion director Hal Rubenstein. "What’s cool is that the iridescent pailettes lengthen her body and accent her curves. It’s one thing to have a good body, another to be proud of it!”

Charles Eshelman/FilmMagic

94. Anne Hathaway in Marc Jacobs, 2009

WHY WE LOVE IT Sporting a strapless Marc Jacobs mini in New York, she reveals a little leg-and a taste for the colorful ‘80s revival.

Kevin Mazur/WireImage

95. Anne Hathaway in Valentino, 2010

WHY WE LOVE IT Not one to shy away from tricky nude hues, Hathaway enhanced her natural glow in a beaded and sequined Valentino tulle gown.

Scott Wintrow/Getty Images

96. Anne Hathaway in Dolce & Gabbana, 2007

WHY WE LOVE IT A bit of black lace peeking out of this flirty Dolce & Gabbana dress, along with a simple updo, says party-ready.

Splash News

97. Anne Hathaway in Zac Posen, 2008

WHY WE LOVE IT The bold lines on this body-hugging Zac Posen design are perfect for a daring actress not afraid to show off her curves.

Jen Lowery/Splash News

98. Anne Hathaway in Chloé, 2010

WHY WE LOVE IT The classic tailoring in Chloe’s cream-colored suit shows Hathaway ready for business at an Academy Awards event.

Jason Merritt/Getty Images

99. Anne Hathaway in Giorgio Armani Privé, 2009

WHY WE LOVE IT Even Miranda Priestly would’ve been wowed by how this Giorgio Armani Prive confection compliments the star’s alabaster skin.

Amy Graves/Elevation Photos

100. Anne Hathaway in Valentino, 2009

WHY WE LOVE IT At a party to fete Valentino, the actress pays homage to the house in a floral silk dress and regal red coat.

Deryck Lewis/WireImage

101. Anne Hathaway in Chanel, 2008

WHY WE LOVE IT The pearlized glass-stone neckline on this chic Chanel number draws the eye upward to her radiant smile.

JPI Studios

102. Anne Hathaway in Marchesa, 2008

WHY WE LOVE IT In this column gown “she’s the epitome of Hollywood glamour,” say Marchesa’s Georgina Chapman and Keren Craig.

Stewart Cook/Rex USA

103. Cate Blanchette in Valentino, 2005

“When Valentino approached her to wear one of his dresses to the Oscars the year she was nominated for The Aviator, Blanchett said yes, as long as she was the only one to wear Valentino. She doesn’t dress like anyone else," says InStyle fashion director Hal Rubenstein.

Brendan Beirne/Rex USA

104. Cate Blanchett in Balenciaga, 2008

WHY WE LOVE IT For her hometown premiere of The Curious Case of Benjamin Button, the Aussie shone in a Balenciaga sheath.

Steve Granitz/WireImage

105. Cate Blanchett in Dries Van Noten, 2008

WHY WE LOVE IT Pregnancy didn't stop this mom-to-be from flaunting her unique style in a breath-taking amethyst Dries Van Noten gown.

Jennifre DuMont/BEImages

106. Cate Blanchett in Dior, 2003

WHY WE LOVE IT Not just for the boys! The acclaimed actress looked dapper in a Dior Homme suit at the Directors Guild of America awards.

Vince Bucci/Getty Images

107. Cate Blanchett in Giorgio Armani Privé, 2007

WHY WE LOVE IT "Cate's luminescent talent shimmers even brighter than this Armani Privé dress," says Giorgio Armani of the Oscars gown.

Tammie Arroyo/AFF-USA

108. Cate Blanchett in Donna Karan, 2004

WHY WE LOVE IT "I loved the drama of deep red against Cate's perfect pale skin," said Donna Karan of the star's Golden Globes gown.

Dave Hogan/Getty Images

109. Cate Blanchett in Prada, 2000

WHY WE LOVE IT Not one to shy away from tricky metallics, the actress enhanced her natural glow in a gold and silver paillette Prada dress.

Hubert Boesl/Landov

110. Cate Blanchett in Alexander McQueen, 2007

WHY WE LOVE IT She turned heads at the Golden Globes wearing Alexander McQueen's lace-laden gown complete with casual pockets.

Dani Abramowicz/FilmMagic

111. Cate Blanchett in Rodarte, 2006

WHY WE LOVE IT The style icon revealed her more romantic side in a ruffled Rodarte dress and matching Christian Louboutin pumps.

Kevin Mazur/WireImage

112. Cate Blanchett in John Galliano, 1999

WHY WE LOVE IT Her John Galliano gown with a cut-down-to-there panel was seductive in an oh-so-beautiful way for the Oscars.

120. Jessica Alba in Calvin Klein, 2006

121. Jessica Alba in Miu Miu, 2009

WHY WE LOVE IT She can do edgy: One part Morticia Addams, all parts sophisticated, the star stepped out in a cool Miu Miu ensemble.

Kevin Mazur/WireImage

122. Jessica Alba in Versace, 2006

WHY WE LOVE IT For her first Academy Awards appearance, Alba showed off her knockout figure in a formfitting Versace number.

Jen Lowery/Startraks

123. Leighton Meester in Bottega Veneta, 2009

“Meester is anything but conventional. She is having a blast with fashion, and this Bottega Veneta dress is no exception," says InStyle fashion director Hal Rubenstein. "The fluidity of this goddess gown is pure glamour. “

Dominique Charriau/WireImage

124. Leighton Meester in Louis Vuitton, 2009

WHY WE LOVE IT "I've become way more expressive with fashion," says the actress, here in head-to-toe Louis Vuitton at an event in Paris.

Jamie McCarthy/WireImage

125. Leighton Meester in Nina Ricci, 2008

WHY WE LOVE IT With her pulled-back hair and soft makeup, Meester lets this strapless Nina Ricci dress take the spotlight.

Andrew H. Walker/Getty Images

126. Leighton Meester in Proenza Schouler, 2009

WHY WE LOVE IT A less daring woman would shy away from so much shine, but she aces a Proenza Schouler outfit, muting it with dark hose.

Jamie McCarthy/WireImage

127. Leighton Meester in Valentino, 2007

WHY WE LOVE IT A floor-length, off-the-shoulder Valentino in chocolate brown is a warm complement to Meester's rosy complexion.

Charles Sykes/AP

128. Leighton Meester in Lanvin, 2009

WHY WE LOVE IT Appearing on The Late Show with David Letterman, the star looks elegant in Lanvin and an Azzedine Alaïa belt.

Splash News

129. Leighton Meester in Marc Jacobs, 2010

WHY WE LOVE IT She sings, she acts, she's whimsical-especially in a Marc Jacobs gown and gold-leaf crown by Cathy Waterman.

Billy Farrell/PatrickMcMullan.com/Sipa Press

130. Leighton Meester in Proenza Schouler, 2009

WHY WE LOVE IT "As for shoes, the edgier the better!" says her stylist Logan Horne, here in Proenza Schouler with studded Brian Atwood pumps.

Amy Sussman/Getty Images

131. Leighton Meester in Marios Schwab, 2009

WHY WE LOVE IT "Yes, this is a strong piece," says London designer Marios Schwab. "But Leighton has the attitude to pull off a graphic print."

Brian Zak/Sipa Press

132. Leighton Meester in Jil Sander, 2009

WHY WE LOVE IT It's hard to imagine the 24-year-old going conservative in a suit, but one with shorts by Jil Sander keeps the outlook fresh.

Janet Gough/CelebrityPhoto

133. Eva Mendes in Dior, 2009

“In the midst of an economic crisis, this fearless Dior dress brought everyone’s spirits up. Mendes knows how to dress for her body and simply has fun with fashion," says InStyle fashion director Hal Rubenstein.

Joe Kohen/WireImage

134. Eva Mendes in Calvin Klein, 2009

WHY WE LOVE IT "Whenever I wear Calvin Klein Collection I feel effortlessly beautiful," she says. "I can't ask for more than that!"

135. Eva Mendes in D&G, 2008

WHY WE LOVE IT On anyone else, D&G's dainty dress would be overly girlie, yet with Mendes's confidence it's all grown-up.

Neil Rasmus/Patrick McMullan

136. Eva Mendes, 2009

WHY WE LOVE IT At a Calvin Klein Collection show, the face (and body) of the lingerie and denim lines chose a reserved sheath.

Neilson Barnard/Getty Images

137. Eva Mendes in Donna Karan, 2009

WHY WE LOVE IT "This look is timeless and modern, but Eva makes it her own," says Donna Karan of Mendes in her classic separates.

138. Eva Mendes in Philosophy di Alberta Ferretti, 2007

WHY WE LOVE IT Up or down, her hair is always glossy and styled—like this soft updo with a Philosophy di Alberta Ferretti column.

Nicolas Khayat/Rex USA

139. Eva Mendes in Lancetti, 2008

WHY WE LOVE IT In Paris she put the exclamation point—rouge Christian Louboutin heels!—on a vintage Lancetti dress.

Lawrence Lucier/FilmMagic

140. Eva Mendes, 2007

WHY WE LOVE IT "The bold color worked well against Eva's complexion," says designer Francisco Costa of the star in Calvin Klein Collection. "She truly glowed."

SGranitz/WireImage

141. Eva Mendes in Giorgio Armani, 2002

WHY WE LOVE IT Dressed in a Giorgio Armani pantsuit at an L.A. film premiere, the actress took a menswear look into sexy new territory.

Mark Mainz/Getty Images

142. Eva Mendes in Gucci, 2005

WHY WE LOVE IT Mendes—who enjoys experimenting with fashion—shimmered in this Gucci gown, with just a bit of blush and a soft red lip.

Ethan Miller/Getty Images

143. Rachel McAdams in Emanuel Ungaro, 2009

“There’s something very old Hollywood glamour about her look," says InStyle fashion director Hal Rubenstein. "This Emanuel Ungaro mini brings her back to that romantic place, while still looking modern.”

144. Rachel McAdams in Phillip Lim, 2009

145. Rachel McAdams in L'Wren Scott, 2009

WHY WE LOVE IT A Brian Reyes trench, L'Wren Scott dress, and oversize Bally bag all added up to a polished everyday look.

Eric Neitzel/WireImage

146. Rachel McAdams in Miu Miu, 2006

WHY WE LOVE IT For an Oscar ceremony, the actress chose an unconventional color-canary yellow-in a Miu Miu gown.

Lionel Hahn/Abaca

147. Rachel McAdams in Yigal Azrouë, 2005

WHY WE LOVE IT "Her look captures casual elegance," says Yigal Azrouël of the star in his hand-embroidered silk-cotton design.

Andrew Marks/Retna

148. Rachel McAdams in Gucci, 2007

WHY WE LOVE IT The actress donned Gucci for a Toronto premiere, accentuating her svelte figure with a pop of crimson.

David X Prutting/Patrick McMullan

149. Rachel McAdams in Derek Lam, 2009

WHY WE LOVE IT Not one to shy away from a bright hue (or a new hair color), she cinched a cobalt sheath by Derek Lam with a turquoise belt.

150. Rachel McAdams in Abaeté, 2009

WHY WE LOVE IT The 31-year-old loves pattern and prints. This one-shoulder Abaeté dress showed how artfully she pulls them off.

Jim Spellman/WireImage

151. Rachel McAdams in Emilio Pucci, 2009

WHY WE LOVE IT How low can she go? The fashion lover was daring in Emilio Pucci. Strong eyes, cheeks and lips give her a sexy confidence.

Denis Guignebourg/ABACAUSA

152. Rachel McAdams in Stella McCartney, 2009

WHY WE LOVE IT In France, McAdams revealed how Stella McCartney lace can be both sophisticated and un peu provocateur.

Rex USA

153. Megan Fox in Roberto Cavalli, 2009

“After Fox wore this barely-there number to a premiere, every last red Cavalli dress sold out in three days. Everyone was talking about the way she looked," says InStyle fashion director Hal Rubenstein.

John Sciulli/Berliner Studio/BEImages

154. Megan Fox in Valentino, 2009

WHY WE LOVE IT With voluminous barrel curls and mile-long lashes, Fox is pinup perfect vamping in a Valentino lace mini.

Frazer Harrison/Getty Images

155. Megan Fox in Ralph Lauren, 2009

WHY WE LOVE IT For her debut at the Golden Globes, Fox chose a curve-enhancing Ralph Lauren Collection stunner under a super-sleek bun.

Mark Von Holden/WireImage

156. Megan Fox in Stella McCartney, 2009

WHY WE LOVE IT In a Stella McCartney leopard-print T and biker jacket, the actress proves that casual can turn heads too.

Rex USA

157. Megan Fox in Giorgio Armani Privé, 2009

WHY WE LOVE IT Though she's inked with tattoos (check out Marilyn Monroe), her vibe is elegant in this fuchsia Giorgio Armani Privé.

Gilbert Flores/CelebrityPhoto

158. Megan Fox in Kaufmanfranco

WHY WE LOVE IT Screen queen or Grecian princess? Fox rules in a Kaufmanfranco toga dress draped over her bronze skin.

Frederick M. Brown/Getty Images

159. Megan Fox in Calvin Klein, 2007

WHY WE LOVE IT At an awards show, she sparks serious heat in a Calvin Klein Collection sheath. Animal-print YSLs lift the 5-foot-6 star above the fray.

Jun Sato/WireImage.com

160. Megan Fox in Donna Karan, 2009

WHY WE LOVE IT Fox may be swathed in layer upon layer of Donna Karan Couture satin, yet she still manages to show a little leg.

Tony Barson/WireImage

161. Megan Fox, 2009

WHY WE LOVE IT "Megan doesn't need help standing out," says Giorgio Armani of his current lingerie model. "She's provocative and beautiful."

Richie Buxo/Splash News

162. Megan Fox in Gucci, 2009

WHY WE LOVE IT In Gucci's metallic blazer, Fox easily combines classic tailoring with rock and roll flash at Comic-Con in San Diego.

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163. Keira Knightley in Vera Wang, 2006

“The rich burgundy color of this Vera Wang gown is unbelievable," says InStyle fashion director Hal Rubenstein. "Knightley has a great sense for color, and always chooses tones that get her noticed. She dresses with a French sensibility even though she’s British.”

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164. Keira Knightley in Valentino, 2006

WHY WE LOVE IT Nominated for Pride and Prejudice, the British star donned a Valentino gown and Cartier jewels at the Golden Globes.

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165. Keira Knightley in Chanel, 2008

WHY WE LOVE IT A chic creature of habit, she chose Chanel again for a screening in New York and paired it with Gina shoes, another favorite.

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166. Keira Knightley in Chanel, 2008

WHY WE LOVE IT At an event in Scotland, the 24-year-old channeled the 1930s in a jumpsuit and sequined blazer, both from Chanel.

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167. Keira Knightley in Rodarte, 2007

WHY WE LOVE IT It took 100 hours to create this Rodarte number, but "all you see is how beautiful she is," say designers Kate and Laura Mulleavy.

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168. Keira Knightley in Gucci, 2006

WHY WE LOVE IT Gucci's metallic jersey dress was liquid gold at the London premiere of Pirates of the Caribbean: Dead Man's Chest.

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169. Keira Knightley in Roland Mouret, 2005

WHY WE LOVE IT She's totally in check: Knightley showed a love for classic tailoring in Roland Mouret at the Toronto Film Festival.

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170. Keira Knightley in 3.1 Phillip Lim, 2008

WHY WE LOVE IT "Effortless and cool," says Phillip Lim of the star in his 3.1 Phillip Lim dress with a Wren jacket and Gina shoes.

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171. Keira Knightley in Calvin Klein, 2005

WHY WE LOVE IT At the N.Y.C. debut of Pride and Prejudice, the actress chose another bold hue, in a stunner by Calvin Klein Collection.

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172. Keira Knightley in Matthew Williamson, 2005

WHY WE LOVE IT "Like Keira, this is young and playful," says Matthew Williamson of his design. She wore it with bangles for a London premiere.

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173. Jennifer Connelly in Balenciaga, 2007

“The metallic shine of this Balenciaga dress works well with her pale skin tone. The short silhouette and hair worn down keep the look young and modern," says InStyle fashion director Hal Rubenstein.

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174. Jennifer Connelly in Balenciaga, 2005

WHY WE LOVE IT At the Costume Institute gala, "everyone was horrified," says designer Nicholas Ghesquière of this short Balenciaga. "But after she did it, short was cool."

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175. Jennifer Connelly in Alexander McQueen, 2005

WHY WE LOVE IT The roses on these Roger Vivier stilettos sweetly offset the plunging neckline of Alexander McQueen's LBD.

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176. Jennifer Connelly in Oscar de la Renta, 2007

WHY WE LOVE IT The mother of two radiated in red, courtesy of de la Renta. "Her style reflects her individuality and spirited nature," he says.

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177. Jennifer Connelly in Versace, 2007

WHY WE LOVE IT Connelly complemented her floral-motif Versace by matching it to her cream Christian Louboutin heels.

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178. Jennifer Connelly in Roberto Cavalli, 2004

WHY WE LOVE IT "Black accents her eyes and pale skin," says stylist Leslie Fremar, who dressed Connelly in this suit by Roberto Cavalli.

180. Jennifer Connelly in Narciso Rodriguez, 2002

WHY WE LOVE IT The Golden Globe winner dispensed a lesson in chic, punctuating her slinky Narciso Rodriguez gown with a fresh camellia.

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181. Jennifer Connelly in Oscar de la Renta, 2005

WHY WE LOVE IT "She always carries herself with such grace and poise," Oscar de la Renta says of the actress, elegant in his eyelet dress.

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182. Jennifer Connelly in Oscar de la Renta, 2007

WHY WE LOVE IT In Oscar de la Renta at the Tokyo premiere of Blood Diamond, Connelly's main accessory was a giant, asymmetrical collar.

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183. Carey Mulligan in Vionnet, 2010

InStyle fashion director Hal Rubenstein says, “Mulligan doesn’t run to the safety of a solid for the red carpet. The print of this Vionnet gown is romantic, while the shape is modern. She’s got a level of awareness and quirkiness that sets her apart from other actresses.”

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184. Carey Mulligan in Lanvin, 2010

WHY WE LOVE IT The newcomer gives a cherry red Lanvin gown an extra bite of cool by pinning a brooch by the French label on her hip.

Mark Mainz/AP

185. Carey Mulligan in Prada, 2010

WHY WE LOVE IT Picture-perfect! The 25-year-old dons a Prada dress made from a vintage-inspired print of an Italian cityscape.

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186. Carey Mulligan in Nina Ricci, 2010

WHY WE LOVE IT Creative on and offscreen, she enlivens a Nina Ricci stunner by turning a Fred Leighton necklace into a headband.

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187. Carey Mulligan in The Row, 2010

WHY WE LOVE IT Showing a penchant for hip designers, Mulligan is all wrapped up in a belted python jacket by The Row.

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188. Carey Mulligan in RM by Roland Mouret, 2010

WHY WE LOVE IT To accessorize her sleek RM by Roland Mouret dress, she chooses strappy black heels (her go-to) from Fendi.

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189. Carey Mulligan in Miu Miu, 2010

WHY WE LOVE IT In a Miu Miu mini with oversize pockets, the ingénue gives the Met's Costume Institute Gala a fun, youthful vibe.

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190. Carey Mulligan in Bottega Veneta, 2010

WHY WE LOVE IT The actress channels her Swinging '60s character from An Education in a marigold full-skirted dress by Bottega Veneta.

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191. Carey Mulligan in Lanvin, 2010

WHY WE LOVE IT At an event in L.A., the star's glossy lips and flush cheeks perfectly complement a rosy one-shoulder Lanvin.

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192. Carey Mulligan in Prada, 2010

WHY WE LOVE IT The charms on this Prada bustier (tiny forks and knives!) prove Mulligan's cutting edge credentials on the red carpet.

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193. Kate Beckinsale in Calvin Klein, 2009

“The bias cut of this J. Mendel gown shows off Beckinsale’s curves. She always incorporates one element to make the look a standout, and far from minimal," says InStyle fashion director Hal Rubenstein.

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194. Kate Beckinsale in Calvin Klein, 2009

WHY WE LOVE IT The English rose revealed her edgier side (and new bangs!) in leather Calvin Klein Collection during N.Y.C.'s Fall Fashion Week.

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195. Kate Beckinsale in Gucci, 2002

WHY WE LOVE IT In Tom Ford for Gucci, the stunner chose romance over va-va-va-voom with fresh, dewy makeup and a pile of curls.

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196. Kate Beckinsale in Hervé Léger, 2008

WHY WE LOVE IT Beckinsale showed us how to be both sexy and ladylike in a below-the-knee Hervé Léger by Max Azria bandage dress.

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197. Kate Beckinsale in Nina Ricci, 2006

WHY WE LOVE IT Egyptian-inspired accessories and a sleek pony were perfect complements to her violet Nina Ricci gown.

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198. Kate Beckinsale in Oscar de la Renta, 2006

WHY WE LOVE IT "This dress brings out her strength and confidence," says designer Oscar de la Renta. "The look is absolute glamour."

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199. Kate Beckinsale in Balenciaga, 2009

WHY WE LOVE IT The star mom of 11 year-old Lily was crowned the sexiest woman alive by Esquire, but kept things demure in this Balenciaga sheath.

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200. Kate Beckinsale in Donna Karan, 2004

WHY WE LOVE IT "I love Kate in nude," says Donna Karan, creator of this gown for a premiere of The Aviator. "Her spirit helps enhance the dress."

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201. Kate Beckinsale in Givenchy, 2001

WHY WE LOVE IT At a London premiere, Beckinsale pulled off casual yet flirty separates from Givenchy by Alexander McQueen.